Doses de adubo de liberação lenta para produção de porta-enxertos de seringueira

Abstract

In the traditional method of growing seedlings of rubber tree readily available fertilizer have been used in supplies to promote the rapid uptake and leaching of nutrients, which are not suitable for fertilization of seedlings grown in hanging baskets, containing soft and porous substrate and subject to watered daily. A possible alternative is the use of slow-release fertilizers which provide nutrients throughout the production cycle without losses. This work was carried out at Embrapa Transferência de Tecnologia - Escritório de Negócios de Goiania, in order to study the effects of doses of slow-release fertilizer (SRF) on the development of rubber tree rootstock. A formulation with release scheduled for 8-9 months was used, containing N (15%), P2O5 (9%), K2O (12%), Mg (1%), S (2,3%), B (0,02%), Cu (0,05%), Fe (1%), Mn (0,06%), Mo (0,02%) and Zn (0,05%). The SRF was incorporated into the substrate at 0, 3, 6 and 9 g / L, before filling the containers, which were supplemented with the same substrate (Rendimax Floreira) and the same dose of SRF after the maturation of the fourth leaf launch. The experimental design was randomized blocks with four treatments (doses of SRF) and eight repetitions of 20 plants per plot. Held on till three seeds per container processing, thinning out the weaker plants at 60 days of age, leaving only one in each container. The irrigation of the nursery was done by spraying in the first 60 days and then drip into each container. At eight months, the development of rootstocks was assessed based on plant height, the stem diameter (SD) to 5 cm in girth and total dry matter of shoots and roots, which were submitted to variance and regression analysis. The nutrient content and the percentage of plants suitable for grafting (SD ≥ 1.0 cm) were also evaluated, noting that the yield and nutrition of rootstocks can be made using SRF at the dose of 6 g per liter of substrate.